Hi,
One way to do it (I don't know if it is the best) is to create the additional "Selected files" folders inside the session folder (this is important so everything remains inside the session) using your computer file system. The next step is to add each of those "Selected files" folders to the "Session Favorites" in C1.
- Add also the original "Selected" Folder to the "Session Favorites"
- Now you can select the "Active" Selected files folder by right click (or equivalent) on the desired folder and select "Set as selects folder".

This will be the folder where an image will be moved to when you click Ctrl+J (or the shortcut you have to send images to the Selects folder). You can change this settings as often as you want, the only limitation is that there can be only one "Active" selects folder at a time (as far as I know). The Active Selects folder will have an icon with an arrow in the "Session Favorites"

- To move from one folder to another just drag and drop inside C1 from one folder to another or move to the Active Selects folder
- Do not move the photos outside of C1, because you might lose the corresponding adjustment folders
Regards